1. Field of the Invention
The invention relates to the field of chemical battery, and more particularly to a method for modifying a positive electrode material for a lithium-ion battery.
2. Description of the Related Art
As a new generation of high-energy battery, the lithium-ion battery features light weight, high power density, high working voltage, and pollution free. Positive electrode materials are critical for manufacturing of the lithium-ion secondary battery, and are the primary factor to determine the performance and the value of the lithium-ion battery.
Studies of the positive electrode material of the lithium-ion battery are mainly focused on lithium-transition metal composite oxides, which include: LiCoO2, LiFePO4, LiNiO2, LiV3O8, LiMn2O4, and derivatives thereof. These positive electrode materials have different advantages. For example, LiCoO2 has a high voltage, high specific energy, and superb cycle performance, and has been successfully applied in small lithium-ion batteries. LiFePO4 has a relatively high theoretical capacity (170 mAh/g), superb cycle performance and thermal stability, abundant resource, low price, and is environment-friendly. LiNiO2 has a low discharge rate and low requirement on the electrolyte and is pollution free. LiV3O8 has a higher specific capacity and is nontoxic and cheep. LiMn2O4 is characterized in its good stability, pollution free, high working voltage, low price, and convenient synthesis. However, all these materials have a relatively low intrinsic electronic conductivity when serving as the positive electrode materials, thereby seriously affecting high current electrochemical performance and practical application thereof.